358 Scientific Proceedings, Royal Dublin Society. 
avoid confusion), by which if either portion of clock fail to do its 
duty from want of winding, want of electric current, or other 
cause, the connection between the two systems is instantly severed 
automatically. ) 
Various small parts might be mentioned, in which the wants of 
the astronomer have been carefully considered. 
The lamps are the result of long and careful trials. All the steel 
parts are coated with nickel, to arrest oxidation as far as possible. 
Lunar wheels are applied to facilitate the changing from siderial 
to lunar rate. Sliding and screwing counterpoise weights are 
arranged, with special reference to physical work, &c. 
PART 2. 
THE BUILDING AND MINOR INSTRUMENTS. 
| Read December 15th, 1879.] 
I proceed now to describe a few of the general features of the 
Observatory and its instrumental equipment. 
The Building (Plate 25), which being in Cork is, of course, built 
of Cork limestone, consists of an octagonal tower of two stories in 
height, with two wings, E. and W., of a single story in height. The 
lower story of the tower is used partly as an ante-chamber or 
entrance to the Transit and Physical Research Rooms, which con- 
stitute respectively the E. and W. wings, and is partly divided into 
two or three smaller rooms round the equatorial pier, which 
it is intended to utilize for certain arrangements connected with 
the clock system of the observatory and also for chemical room, 
battery room, &e. The wpper story contains the 8-inch equa- 
torial, which I had the pleasure of exhibiting and explaining 
here last session. This upper room is covered by a hemispherical 
dome of fifteen feet diameter. 
The Staircase, by which access is obtained to the upper story, 
is circular, and is contained in the small tower attached to the 
north side of the equatorial tower. 
The East Wing is the transit room, for which | am now preparing 
a 5-inch transit circle, and which is supplied with a transit shutter 
of novel construction. See below. 
The West Wing is intended for physical research and experi- 
ments, and will contain a siderostatic telescope, of peculiar 
construction, which I have the pleasure of exhibiting this evening 
and various appliances of spectroscopic and general researches. 
